Ultrafiltration is a technique or procedure used to describe a process and apparatus utilized to separate dissolved molecules in solution based on the physical size of the molecules. Filtering apparatus, of the kind described, generally employ a thin membrane filter having transverse pores therethrough of predetermined precise opening size calculated to pass or hinder the passage of certain molecules therethrough. One well known ultrafiltration device utilizing an ultrafiltration membrane cell is disclosed and claimed in U.S. Pat. No. 4,715,955, which patent issued Dec. 19, 1987 to D. Friedman one of the inventors named in the present application, and is incorporated by reference in this application. Presently available membrane ultrafiltration cells commonly have effective membrane areas in the range of about 5.0 sq. ft. to about 50.0 sq. ft. Accordingly, a plurality of such Friedman devices are required when a larger scale filtering process is desired, and such a practice includes the complexity of an additional number of fluid flow lines and the need to make additional fluid conduit connections for the additional devices.